1. Field of the Invention
The present invention relates to a semiconductor device fabrication, and more particularly to a method for forming a photosensitive device with color filter.
2. Description of the Prior Art
FIGS. 1 are schematic representations of structures at last stages during the formulation of photo-sensitive device using the conventional, prior technology. Referring to FIG. 1A, a planarized inter-metal dielectric layer 100 with a photo-receiving region 130 is formed. A metal layer 114 is deposited and defined to expose the photo-receiving region 130 on the inter-metal dielectric layer 100. Then, a passivation layer 150 is formed on to protect the sensitive device below.
Referring to FIG. 1B, because a planar layer is needed for following color filter process, a coated planar film 152 or coated spin-on glass with etching-back process is performed. Both planar film 152 and passivation layer 150 are transparent. Then, a color filter process, comprising coating R G B filters, development, etching and top coating, is performed to form color filter 112. Next, another passivation layer 120 is coated on to cover the color filter 112 and planar film 152. FIG. 2 is a flow diagram showing the steps of forming color filter according to the above conventional process with six main steps.
The above description, however, has a high cost and long cycle time because of many steps in the process. Furthermore, multi-transparent layers will give a low transimittance rate and yield.
In accordance with the present invention, a method is provided for forming photo-sensitive device that substantially reduces the cost comparing to the prior method. This is performed by reducing process steps and raw material due to the process steps are reversible.
It is another object that the present invention reduces the cycle time by reducing the planar film and passivation layer for color filter.
It is still another object that this invention increases the transimittance rate by reducing the planar film and yield.
In one embodiment, a planarized insulator with a photo-receiving region formed in is provided. Then, at least one color filter pattern is formed on the photo-receiving region by using conventional method. Next, a conformal conductive layer is formed on said insulator. A passivation layer over said partially fabricated device is formed.